Compositions prepared by the sulfurization of various organic materials including olefins are known in the art, and lubricants containing these compositions also are known. U.S. Pat. No. 4,191,659 describes the preparation of sulfurized olefinic compounds by the catalytic reaction of sulfur and hydrogen sulfide with olefinic compounds containing from 3 to 30 carbon atoms. The compounds are reported to be useful in lubricating compositions, particularly those prepared for use as industrial gear lubricants. U.S. Pat. No. 4,119,549 describes a similar procedure for sulfurizing olefins utilizing sulfur and hydrogen sulfide followed by removal of low boiling materials from said sulfurized mixture.
Sulfur-containing compositions characterized by the presence of at least one cycloaliphatic group with at least two nuclear carbon atoms of one cycloaliphatic group or two nuclear carbon atoms of different cycloaliphatic groups joined together through a divalent sulfur linkage are described in Reissue Patent Re 27,331. The sulfur linkage contains at least two sulfur atoms, and sulfurized Diels-Alder adducts are illustrative of the compositions disclosed in the reissue patent. The sulfur-containing compositions are useful as extreme pressure and anti-wear additives in various lubricating oils.
The lubricant compositions described in Re 27,331 may contain other additives normally used in lubricating oils such as detergents, dispersants, other extreme pressure agents, oxidation- and corrosion-inhibitors, etc. Among the extreme pressure additives described are organic sulfides and polysulfides such as benzylsulfide and phosphosulfuized hydrocarbons; phosphorus esters such as dihydrocarbon and trihydrocarbon phosphites including, for example, dibutyl phosphite, pentylphenyl phosphite, tridecyl phosphite and dipentylphenyl phosphite, etc.
Dialdehydes containing disulfide groups and represented by the formula ##STR2## wherein both R groups are the same alkyl groups of 1 to 18 carbon atoms and both R.sup.1 groups are the same alkyl or aryl groups are described in U.S. Pat. No. 2,580,695. The compounds are reported to be useful as cross-linking agents and as chemical intermediates.
Lubricating compositions containing sulfides having the formula ##STR3## wherein R.sub.1 is a hydrocarbon group, R.sub.2 is hydrogen or a hydrocarbon group, and x is 1 to 2 are described in U.S. Pat. No. 3,296,137. The lubricants can contain other additives including, for example, detergents of the ash-containing type, viscosity index-improving agents, extreme-pressure agents, oxidation-inhibiting agents, friction-improving agents, corrosion-inhibiting and oxidation-inhibiting agents described in the patent are organic sulfides and polysulfides such as benzylsulfide and phosphosulfurized hydrocarbons; phosphorus esters such as dihydrocarbon and trihydrocarbon phosphites including, for example, dibutyl phosphite, pentylphenyl phosphite, tridecyl phosphite and dipentylphenyl phosphite, etc.
Oil-soluble nitrogen-containing compounds prepared by reacting of succinic acid-producting compounds with amines have been described in the prior art as useful ashless dispersants in lubricating oils. Many patents describe the preparation of such compounds and their use in lubricating oils, alone or in combination with other oil additives. Examples of such patents include:
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